There are over 100 journalists and interested parties on a video link, including me, listening in to what's going on in Court 15 of the Rolls Building, part of the High Court.
They include journalists from The Telegraph, The Mail and The Sunday Times.
The press seats in the main court room are full with correspondents, producers and court artists from different news organisations, including the BBC and other broadcasters.
And for those who haven't got a ticket, there's an overspill annexe further down the corridor.
People 'magically' produced phone numbers - Harry's lawyer
Tom Symonds
Home affairs correspondent, reporting from court
Prince Harry's lawyer is turning up the dial in questions to the Mirror's former royal editor Jane Kerr.
David Sherborne is asking about the private investigators Kerr called to get phone numbers for people the Mirror wanted to speak to.
She's given evidence that she called various agencies and they provided numbers which the paper needed when covering "breaking news".
Sherborne asks: "You were working as a senior editor on the news desk of a national newspaper and you seem to have no idea of what you were doing at the time".
Kerr replies: "I knew what I was doing but it was a long time ago."
Prince Harry's lawyer then goes on to say: "You called up people, you had no idea what they did - they magically produced phone numbers and you never asked any questions."
"Yes", said Kerr.
Mood shifts as Harry's lawyer addresses ex-royal editor
Elizabeth Needham-Bennett
Reporting from court
The tone of questioning from David Sherborne - Prince Harry's lawyer - has changed significantly from his earlier exchanges with the prince.
Sherborne is questioning Jane Kerr, a former assistant news editor at the Daily Mirror.
It's not friendly.
"You know, Miss Kerr, this is information that should not have been obtained and used by journalists," he says.
The way he says "Miss Kerr" feels loaded - it's drawn out in emphasis.
Ex-royal editor asked why she didn't mention news editor job
Tom Symonds
Home affairs correspondent, reporting from court
Prince Harry sits next to his lawyers as he listens to former reporter Jane Kerr being cross-examined.
Jane Kerr was the Mirror's royal reporter and then correspondent between 1997 and 2005.
In early questions, she's challenged by Prince Harry's lawyer David Sherborne about why she had to be ordered to come to court by the judge.
She's also challenged on why she didn't mention in her witness statement that she became the assistant news editor of the paper in 2006.
Lawyer Sherborne says she's trying to distance herself from the paper.
A key strand in this case is how far up the management structure there was knowledge of illegal newsgathering.
Former reporter Kerr says she focused her witness statement on her royal reporting duties.
Harry appeared choked up in witness box
Jemma Crew
Reporting from court
As lawyer David Sherborne finished his questioning Prince Harry a few minutes ago, the prince appeared to be slightly choked up.
He was asked by Sherborne - who is his own lawyer - how he had felt to have gone through everything over the last two days in the witness box.
"It’s a lot," he said finally, after a pause.
Analysis
Harry's comment on disappearing mail notifications could be crucial
Dominic Casciani
Legal correspondent, reporting from court
The judge, Mr Justice Fancourt, asked Prince Harry a very important question just before he finished.
He took him back to a part of his witness statement which has been somewhat forgotten over the last two days - but amounts to his alleged personal experience of the tell-tale signs of hacking.
Over four paragraphs of his statement, Prince Harry recalls voice messages on his phone would not appear to be new, even if he had not heard them - or the "new mail" icon on the screen would disappear.
This is important because there is no dispute that phone hacking techniques used by journalists could lead to messages disappearing from phones in this way.
"Can you help by identifying when ... you experienced this strange activity?" asked the judge.
"From the moment I had a mobile phone," replied Prince Harry - meaning around the time he went to Eton as a teenager.
"Are you saying this continued throughout the period?"
"It never stopped," the prince replied.
This exchange - and the credibility or not of what Prince Harry remembers - may turn out to be crucial.
Harry stays in court for ex-royal editor's cross-examination
Prince Harry is staying in court to listen to evidence from Jane Kerr, the Daily Mirror's former royal editor.
She's a witness called by Mirror Group Newspapers, and therefore will be cross-examined by Prince Harry's lawyer David Sherborne.
Kerr - whose byline is on 10 out of the 33 articles being considered by the court - has just been sworn in.
Here she was arriving at the High Court a little earlier:
BBCCopyright: BBC
BreakingHarry finishes giving evidence
Jemma Crew
Reporting from court
Prince Harry has finished giving his evidence and has left the witness box.
After asking him a few final questions, the judge said: "Thank you very much Prince Harry, that really is the end of your evidence".
The press have misled me my whole life - Harry
Jemma Crew
Reporting from court
Prince Harry's lawyer, David Sherborne, brings up an article in The People in September 2008, marked as an exclusive, that said he had been “banned” from returning to military service in Afghanistan.
He asks the prince if he believes he was speculating that unlawful information gathering had taken place for that story.
He replies: "No, I do not.”
After a small pause, he continues: “For my whole life the press have misled me, have covered up wrongdoing, so to be sitting in court knowing that the defence has the evidence in front of them, and Mr Green [the publisher's lawyer] says I’m speculating… I’m not entirely sure what to say about that.”
Court artist scribbles away outside court
Cameras aren't allowed for most UK court hearings - that's why we rely on sketches to depict what's going on.
And, due to the wording of the law, court sketch artists aren't allowed to draw in the courtroom either - although they can make notes.
Here's a snap we've just spotted of court artist Elizabeth Cook working on her sketch of Prince Harry on the street outside the High Court:
PA MediaCopyright: PA Media
At least it's not raining!
Harry: My case is not total speculation
Jemma Crew
Reporting from court
As a reminder, Prince Harry is now speaking to his own barrister, David Sherborne - rather than the Mirror's.
He is asked if he believes his claims of unlawful activity are “in the realm of total speculation” – as put to him in cross-examination repeatedly earlier today.
The prince replies: “No, I don’t. And it is even more destructive that it was used as a headline I think this morning [in the newspapers] against me.”
BreakingI found tracking device on ex-girlfriend Chelsy's car - Harry
Tom Symonds
Home affairs correspondent, reporting from court
Prince Harry's tells the court he once found a tracking device on the car belonging to his ex-girlfriend Chelsy Davy.
At the time the newspapers were interested in a "make or break" holiday Harry had with Davy.
He alleges it was placed by a private investigator, Mike Behr, who the prince has also accused in other cases of targeting him.
He said a friend, Mark Dyer, had also found a tracking device on his car.
ReutersCopyright: Reuters
Prince Harry has been asked about several stories about his ex-girlfriend Chelsy DavyImage caption: Prince Harry has been asked about several stories about his ex-girlfriend Chelsy Davy
BreakingHarry back in the witness box
The lunchbreak is over, and Prince Harry will now face some brief questioning from his own barrister, David Sherborne.
Harry not expected to pop out for a sandwich
Helena Wilkinson
Reporting from court
As court breaks for lunch, outside the building the dozens of camera crews and photographs have set up again either side of the entrance.
They are poised in case Prince Harry emerges.
But it's not like the prince can just pop out to grab a sandwich and a cup of coffee like the rest of us.
So it’s unlikely we’ll see him outside here until later in the day.
EPACopyright: EPA
Analysis
The pattern of Harry's cross-examination
Tom Symonds
Home affairs correspondent, reporting from court
Prince Harry's cross-examination by the Mirror's lawyer Andrew Green ended before the lunchbreak. There was a pattern to the challenges:
The Mirror Group lawyer says:
The information has already been reported by other newspapers, before the Mirror papers get to it.
Prince Harry replies:
That reporting just encourages Mirror journalists to use unlawful techniques to find a new angle.
The lawyer says:
It's worth pointing to the possibility someone in Prince Harry's circle might have talked to a journalist.
Prince Harry says:
The source may have been made up by the journalist.
The lawyer says:
"Palace sources" were aware of what was going on in Prince Harry's private life and leaked to the press.
Prince Harry says:
Those sources would not have known such personal information.
Analysis
Harry didn't crumble
Sean Coughlan
From the High Court
There might be an inner sigh of relief for Prince Harry, now
that the cross-examination by the Mirror’s barrister is over.
If anything, Prince Harry seemed to be getting more
confident in his replies, sparring with his questioner.
There was always going to be a lot of scrutiny over how he
responded – and he didn’t crumble or get irritated. It will be up to the judge
to consider whether he’s been convincing.
There has been a taboo over senior royals giving
evidence in court that stretches back over a century.
But so far, Prince Harry’s
appearance in the witness box has not produced any embarrassing revelations for
the rest of the Royal Family.
Court breaks for lunch - but more to come from Harry
And after that long morning session, the court is breaking for lunch and will be back in an hour.
The prince's own barrister, David Sherborne, says he has a few more questions for Prince Harry, which he'll put to him for around 10 minutes after lunch.
Final clash between Harry and Mirror lawyer
Dominic Casciani
Legal correspondent, reporting from court
Julia QuenzlerCopyright: Julia Quenzler
Lawyer Andrew Green has wrapped up for the Mirror - but not before a final clash between him and the prince.
He asks the prince to identify a single voicemail that he knows was hacked. Prince Harry says there is "hard evidence of suspiciousness," and adds: "I believe that phone hacking started at the Mirror Group."
"You say you were hacked over a 15-year period," the lawyer replies.
"Yes," Prince Harry says.
"Are you claiming damages on the basis that your phone was hacked on daily basis?"
"It could have been," says Prince Harry. "I simply don’t know, My Lord. That’s part of the reason why I’m here."
BreakingHarry's cross-examination ends
Jemma Crew
Reporting from court
The Mirror Group's lawyer Andrew Green has just finished questioning Prince Harry.
I sought legal advice after bumping into lawyer in France - Harry
James Gregory
Reporting from court
Prince Harry says he had not sought legal advice on whether he had a valid claim against Mirror Group Newspaper until he "bumped into" David Sherborne - the lawyer who is representing him in this case - in France in 2018.
He says he details this encounter in his book, Spare.
He tells the court even if he had seen the articles before this, he would not have been allowed to make a claim.
"It was all contained within the Palace and even if I wanted to I wouldn't be allowed to make a claim," he says.
He also claims there was "industrial scale destruction of evidence".
"You constantly refer to destruction of evidence. Where do you get this idea of destruction of evidence by the Mirror Group?" the publisher's lawyer asks.
"My legal team," the prince responds, adding that he believes phone hacking started at the Mirror Group.
Live Reporting
Edited by Dulcie Lee
All times stated are UK
Dozens of journalists in court for big day
Elizabeth Needham-Bennett
Reporting from court
There are over 100 journalists and interested parties on a video link, including me, listening in to what's going on in Court 15 of the Rolls Building, part of the High Court.
They include journalists from The Telegraph, The Mail and The Sunday Times.
The press seats in the main court room are full with correspondents, producers and court artists from different news organisations, including the BBC and other broadcasters.
And for those who haven't got a ticket, there's an overspill annexe further down the corridor.
People 'magically' produced phone numbers - Harry's lawyer
Tom Symonds
Home affairs correspondent, reporting from court
Prince Harry's lawyer is turning up the dial in questions to the Mirror's former royal editor Jane Kerr.
David Sherborne is asking about the private investigators Kerr called to get phone numbers for people the Mirror wanted to speak to.
She's given evidence that she called various agencies and they provided numbers which the paper needed when covering "breaking news".
Sherborne asks: "You were working as a senior editor on the news desk of a national newspaper and you seem to have no idea of what you were doing at the time".
Kerr replies: "I knew what I was doing but it was a long time ago."
Prince Harry's lawyer then goes on to say: "You called up people, you had no idea what they did - they magically produced phone numbers and you never asked any questions."
"Yes", said Kerr.
Mood shifts as Harry's lawyer addresses ex-royal editor
Elizabeth Needham-Bennett
Reporting from court
The tone of questioning from David Sherborne - Prince Harry's lawyer - has changed significantly from his earlier exchanges with the prince.
Sherborne is questioning Jane Kerr, a former assistant news editor at the Daily Mirror.
It's not friendly.
"You know, Miss Kerr, this is information that should not have been obtained and used by journalists," he says.
The way he says "Miss Kerr" feels loaded - it's drawn out in emphasis.
Ex-royal editor asked why she didn't mention news editor job
Tom Symonds
Home affairs correspondent, reporting from court
Prince Harry sits next to his lawyers as he listens to former reporter Jane Kerr being cross-examined.
Jane Kerr was the Mirror's royal reporter and then correspondent between 1997 and 2005.
In early questions, she's challenged by Prince Harry's lawyer David Sherborne about why she had to be ordered to come to court by the judge.
She's also challenged on why she didn't mention in her witness statement that she became the assistant news editor of the paper in 2006.
Lawyer Sherborne says she's trying to distance herself from the paper.
A key strand in this case is how far up the management structure there was knowledge of illegal newsgathering.
Former reporter Kerr says she focused her witness statement on her royal reporting duties.
Harry appeared choked up in witness box
Jemma Crew
Reporting from court
As lawyer David Sherborne finished his questioning Prince Harry a few minutes ago, the prince appeared to be slightly choked up.
He was asked by Sherborne - who is his own lawyer - how he had felt to have gone through everything over the last two days in the witness box.
"It’s a lot," he said finally, after a pause.
Harry's comment on disappearing mail notifications could be crucial
Dominic Casciani
Legal correspondent, reporting from court
The judge, Mr Justice Fancourt, asked Prince Harry a very important question just before he finished.
He took him back to a part of his witness statement which has been somewhat forgotten over the last two days - but amounts to his alleged personal experience of the tell-tale signs of hacking.
Over four paragraphs of his statement, Prince Harry recalls voice messages on his phone would not appear to be new, even if he had not heard them - or the "new mail" icon on the screen would disappear.
This is important because there is no dispute that phone hacking techniques used by journalists could lead to messages disappearing from phones in this way.
"Can you help by identifying when ... you experienced this strange activity?" asked the judge.
"From the moment I had a mobile phone," replied Prince Harry - meaning around the time he went to Eton as a teenager.
"Are you saying this continued throughout the period?"
"It never stopped," the prince replied.
This exchange - and the credibility or not of what Prince Harry remembers - may turn out to be crucial.
Harry stays in court for ex-royal editor's cross-examination
Prince Harry is staying in court to listen to evidence from Jane Kerr, the Daily Mirror's former royal editor.
She's a witness called by Mirror Group Newspapers, and therefore will be cross-examined by Prince Harry's lawyer David Sherborne.
Kerr - whose byline is on 10 out of the 33 articles being considered by the court - has just been sworn in.
Here she was arriving at the High Court a little earlier:
BreakingHarry finishes giving evidence
Jemma Crew
Reporting from court
Prince Harry has finished giving his evidence and has left the witness box.
After asking him a few final questions, the judge said: "Thank you very much Prince Harry, that really is the end of your evidence".
The press have misled me my whole life - Harry
Jemma Crew
Reporting from court
Prince Harry's lawyer, David Sherborne, brings up an article in The People in September 2008, marked as an exclusive, that said he had been “banned” from returning to military service in Afghanistan.
He asks the prince if he believes he was speculating that unlawful information gathering had taken place for that story.
He replies: "No, I do not.”
After a small pause, he continues: “For my whole life the press have misled me, have covered up wrongdoing, so to be sitting in court knowing that the defence has the evidence in front of them, and Mr Green [the publisher's lawyer] says I’m speculating… I’m not entirely sure what to say about that.”
Court artist scribbles away outside court
Cameras aren't allowed for most UK court hearings - that's why we rely on sketches to depict what's going on.
And, due to the wording of the law, court sketch artists aren't allowed to draw in the courtroom either - although they can make notes.
Here's a snap we've just spotted of court artist Elizabeth Cook working on her sketch of Prince Harry on the street outside the High Court:
At least it's not raining!
Harry: My case is not total speculation
Jemma Crew
Reporting from court
As a reminder, Prince Harry is now speaking to his own barrister, David Sherborne - rather than the Mirror's.
He is asked if he believes his claims of unlawful activity are “in the realm of total speculation” – as put to him in cross-examination repeatedly earlier today.
The prince replies: “No, I don’t. And it is even more destructive that it was used as a headline I think this morning [in the newspapers] against me.”
BreakingI found tracking device on ex-girlfriend Chelsy's car - Harry
Tom Symonds
Home affairs correspondent, reporting from court
Prince Harry's tells the court he once found a tracking device on the car belonging to his ex-girlfriend Chelsy Davy.
At the time the newspapers were interested in a "make or break" holiday Harry had with Davy.
He alleges it was placed by a private investigator, Mike Behr, who the prince has also accused in other cases of targeting him.
He said a friend, Mark Dyer, had also found a tracking device on his car.
BreakingHarry back in the witness box
The lunchbreak is over, and Prince Harry will now face some brief questioning from his own barrister, David Sherborne.
Harry not expected to pop out for a sandwich
Helena Wilkinson
Reporting from court
As court breaks for lunch, outside the building the dozens of camera crews and photographs have set up again either side of the entrance.
They are poised in case Prince Harry emerges.
But it's not like the prince can just pop out to grab a sandwich and a cup of coffee like the rest of us.
So it’s unlikely we’ll see him outside here until later in the day.
The pattern of Harry's cross-examination
Tom Symonds
Home affairs correspondent, reporting from court
Prince Harry's cross-examination by the Mirror's lawyer Andrew Green ended before the lunchbreak. There was a pattern to the challenges:
The Mirror Group lawyer says:
The information has already been reported by other newspapers, before the Mirror papers get to it.
Prince Harry replies:
That reporting just encourages Mirror journalists to use unlawful techniques to find a new angle.
The lawyer says:
It's worth pointing to the possibility someone in Prince Harry's circle might have talked to a journalist.
Prince Harry says:
The source may have been made up by the journalist.
The lawyer says:
"Palace sources" were aware of what was going on in Prince Harry's private life and leaked to the press.
Prince Harry says:
Those sources would not have known such personal information.
Harry didn't crumble
Sean Coughlan
From the High Court
There might be an inner sigh of relief for Prince Harry, now that the cross-examination by the Mirror’s barrister is over.
If anything, Prince Harry seemed to be getting more confident in his replies, sparring with his questioner.
There was always going to be a lot of scrutiny over how he responded – and he didn’t crumble or get irritated. It will be up to the judge to consider whether he’s been convincing.
There has been a taboo over senior royals giving evidence in court that stretches back over a century.
But so far, Prince Harry’s appearance in the witness box has not produced any embarrassing revelations for the rest of the Royal Family.
Court breaks for lunch - but more to come from Harry
And after that long morning session, the court is breaking for lunch and will be back in an hour.
The prince's own barrister, David Sherborne, says he has a few more questions for Prince Harry, which he'll put to him for around 10 minutes after lunch.
Final clash between Harry and Mirror lawyer
Dominic Casciani
Legal correspondent, reporting from court
Lawyer Andrew Green has wrapped up for the Mirror - but not before a final clash between him and the prince.
He asks the prince to identify a single voicemail that he knows was hacked. Prince Harry says there is "hard evidence of suspiciousness," and adds: "I believe that phone hacking started at the Mirror Group."
"You say you were hacked over a 15-year period," the lawyer replies.
"Yes," Prince Harry says.
"Are you claiming damages on the basis that your phone was hacked on daily basis?"
"It could have been," says Prince Harry. "I simply don’t know, My Lord. That’s part of the reason why I’m here."
BreakingHarry's cross-examination ends
Jemma Crew
Reporting from court
The Mirror Group's lawyer Andrew Green has just finished questioning Prince Harry.
I sought legal advice after bumping into lawyer in France - Harry
James Gregory
Reporting from court
Prince Harry says he had not sought legal advice on whether he had a valid claim against Mirror Group Newspaper until he "bumped into" David Sherborne - the lawyer who is representing him in this case - in France in 2018.
He says he details this encounter in his book, Spare.
He tells the court even if he had seen the articles before this, he would not have been allowed to make a claim.
"It was all contained within the Palace and even if I wanted to I wouldn't be allowed to make a claim," he says.
He also claims there was "industrial scale destruction of evidence".
"You constantly refer to destruction of evidence. Where do you get this idea of destruction of evidence by the Mirror Group?" the publisher's lawyer asks.
"My legal team," the prince responds, adding that he believes phone hacking started at the Mirror Group.